8S globulin of mungbean [Vigna radiata (L.) Wilczek]: cloning and characterization of its cDNA isoforms, expression in Escherichia coli, purification, and crystallization of the major recombinant 8S isoform

Three isoforms of the cDNA of the major 8S globulin of mungbean, 8Salpha, 8Salpha', and 8Sbeta, were isolated, cloned, and characterized. The cDNA sequences of 8Salpha, 8Salpha', and 8Sbeta had open reading frames of 1362, 1359 or 1362, and 1359 bp, respectively, which code for 454, 453 or 454, and 453 amino acids corresponding to molecular weights of 51 973, 51 627 or 51 758, and 51 779, respectively. Homology in terms of cDNA and amino acid sequences was 91-92% between 8Salpha and 8Salpha', 87% between 8Salpha and 8Sbeta, and 86-88% between 8Salpha' and 8Sbeta. The signal peptide was found to be 1-25, 1-24 or 25, and 1-23 for 8Salpha, 8Salpha', and 8Sbeta, respectively, using the signalP website (Nielsen, H.; Engelbrecht, J.; Brunak, S.; von Heijne, G. Protein Eng. 1997, 10, 1-6). The propeptide was determined to be IVHREN. A single site for glycosylation (N-X-S/T) was observed about 90 amino acids from the C terminus. Homology between mungbean 8S isoforms and other 7-8S proteins ranged from 45 to 68% within members of the legume family and 29 to 34% for crops of different species. The major isoform 8Salpha was expressed in Escherichia coli and purified by successive ammonium sulfate fractionation, hydrophobic interaction, and Mono Q column chromatography. The recombinant 8Salpha, but not the native form, was successfully crystallized producing rhombohedral crystals.     

Conservation value of dispersed tree cover threatened by pasture management

Trees dispersed in pastures are a prominent feature of many Central American landscapes, particularly in cattle producing regions where farmers retain trees to serve as shade, fodder, timber and firewood. The presence of dispersed trees in pastures is often considered as important for the conservation of biodiversity by providing habitat and enhancing landscape connectivity. However, despite their critical productive and environmental roles, little is known about tree distribution within pastures or how farmers’ management decisions influence the trees themselves and their impact on farm productivity and biodiversity conservation. Here, we present a synthesis of (a) the abundance, composition, and size of dispersed trees in four important cattle producing regions of Costa Rica (Caňas and Río Frío) and Nicaragua (Rivas and Matiguás), based on inventory of 18,669 trees on 1492 ha of pasture, (b) the local knowledge, management and use of trees by cattle farmers, and (c) opportunities for ensuring sustainable management of dispersed trees in pasture-dominated landscapes. Dispersed trees were common in all four landscapes, with mean frequency ranging from 8.0 trees ha⁻¹ in Caňas to 33.4 trees ha⁻¹ in Matiguás. A total of 255 tree species were found in pastures across the four landscapes. The total number of tree species per landscape varied from 72 in Rivas to 101 in Caňas and Rio Frio, with mean species richness per farm ranging from 22.9 in Rio Frio to 45.9 in Matiguás. In all four landscapes, a handful of tree species dominated the pastures, with the ten most abundant species in each landscape accounting for >70% of all trees recorded. Most of these common tree species provide fruits or foliage eaten by cattle, or are important timber or firewood species, and are deliberately retained by farmers for these uses. In all four landscapes, farmers had a detailed knowledge of tree attributes affecting pasture and animal productivity, and influenced tree cover through pasture management activities and occasional tree cutting. Current farm management practices are gradually decreasing the diversity of trees in pastures, and in some cases also tree density, reducing their contribution to farm productivity and biodiversity conservation. To reverse this trend, incentives are required to encourage cattle farmers to retain and enhance tree cover in pastures, through the adoption of pasture management practices that favor the regeneration and persistence of a diverse range of tree species.     

Evidence for ozone formation in human atherosclerotic arteries

Here, we report evidence for the production of ozone in human disease. Signature products unique to cholesterol ozonolysis are present within atherosclerotic tissue at the time of carotid endarterectomy, suggesting that ozone production occurred during lesion development. Furthermore, advanced atherosclerotic plaques generate ozone when the leukocytes within the diseased arteries are activated in vitro. The steroids produced by cholesterol ozonolysis cause effects that are thought to be critical to the pathogenesis of atherosclerosis, including cytotoxicity, lipid-loading in macrophages, and deformation of the apolipoprotein B-100 secondary structure. We propose the trivial designation "atheronals" for this previously unrecognized class of steroids.     

Reducing endogenous tau ameliorates amyloid beta-induced deficits in an Alzheimer's disease mouse model

Many potential treatments for Alzheimer's disease target amyloid-beta peptides (Abeta), which are widely presumed to cause the disease. The microtubule-associated protein tau is also involved in the disease, but it is unclear whether treatments aimed at tau could block Abeta-induced cognitive impairments. Here, we found that reducing endogenous tau levels prevented behavioral deficits in transgenic mice expressing human amyloid precursor protein, without altering their high Abeta levels. Tau reduction also protected both transgenic and nontransgenic mice against excitotoxicity. Thus, tau reduction can block Abeta- and excitotoxin-induced neuronal dysfunction and may represent an effective strategy for treating Alzheimer's disease and related conditions.